Just so you know, a piano like that is supposed to take up 2x2 tiles. Which means that it's either an impossible structure or embedded into the wall in this screenshot. I believe it is intended be neither.
Edit: Wait, you've done it with the cupboards too. It must be a stylistic choice. Albeit, I would say, a bad one.
Well, I originally did that so the player would have more room to move around AND AT LEAST IT LOOKS NICE.
Anyhoo, this screenshot is very old and I have since improved on structures like that (I think.)